Method for treating slop wax distillate



I distillate.

Patented July 17,

retrofit PATENT QFFICE METHOD FOR TREATING SLOP WAX DISTILLATE Rudolph C. Osterstromand Gary R. Wagner, Chicage, 111., assignors to The Pure Oil Company, Chicago, 111., a corporation of Ohio No Drawing. Application March 19, 1932, Serial No. 600,059

5 Claims.

This invention relates to the refining of hydrocarbon lubricating ofls, especially lubricating oils employing in their composition residual wax To render such a distillate suitable for use in lubricants, it has been customary to subject the same to distillation whereby to remove its usable viscous fractions from its undesirable heavy wax fractions which interfere with the lubricating properties of the distillate when the resulting lubricating oils formed therefrom are exposed to low temperatures. This distillation or re-running of the so-called slop wax distillate requires careful regulation in order to avoid cracking of the distillate and its resulting impairment as a lubri ating oil stock.

It is therefore an object of the present invention to provide a method for treating slop wax distillate whereby through the addition thereto of selected hydrocarbon oils, hereinafter more specifically defined, the normal pour point of the distillate will be desirably decreased without involving the necessity of re-running the distillate with accompanying loss of certain of its desired viscous fractions, the likelihood of cracking the distillate and the necessary costs of such re-running, so that the distillate may be further processed by centrifuging and reduced to a desired state of refinement and avoiding additional heating thereof.

The invention may be practiced by producing a mixture containing 27 per cent. slop wax distillate, 2.6 per cent. petrolatum, 0.4 per cent. of a residual synthetic hydrocarbon oil produced by the non-destructive distillation of a relatively heavy, cracked, unsaturated hydrocarbon oil with aluminum chloride and 70 per cent. Sharples naphtha cooled to 28 F. This mixture may then be centrifuged and the pour point on the processed material will range from zero to 15 F. By this operation, it is practicable to dewax slop wax distillate without losing the major part of its viscous oil content through cracking.

This operation is rendered feasible by the pour test lowering properties of the synthetic hydrocarbon oil which constitutes but a small percentage of the mixture. The nature of this synthetic oil and methods for producing the same have been set forth in detail in the sole copending applications of the applicant, R. C. Osterstrom,Serial Numbers 576,650; 575,871; 576,127 and 595,152. Therefore, no claim is made to that oil per se in the present application, as the invention herein deals more particularly with the use of said oil in conjunction with slop wax distillate, whereby direct use of the latter may be made in refining operations in single admixture with the other oils or compounds specified without re-distilling such distillate to remove high boiling constituentsand thereby depriving the 7 same of certain viscous fractions which should be retained in the distillate.

The improved synthetic oil which is blended with the distillate may be produced, as set forth in the above identified applications, by removing from a vapor phase cracking operation, wherein motor fuel distillate is produced from higher boiling hydrocarbon oils, a condensate, usually of higher boiling range than motor fuels. This con densate, due to high temperature (1000 to 1200" F.) ne essa-rily involved in vapor phase cracking systems, is characterized by a high percentage of unsaturated hydrocarbons, and responds readily to polymerization reactions when heated to non-cracking temperatures in the presence of a metallic halide, such as aluminum chloride, to produce a viscous residual oil from which the lower boiling compounds, the polymerizing catalyst and other incidental impurities may be conveniently removed. We, therefore, refer to this carbon oil as a blending medium for lowering the pour test of ordinary lubricating oils, but in the present instance, we have found said oil to be very efiicacious in the operation of dewaxing slop wax distillate, without re-running, by reducing it to a state of fluidity in which it may be centrifuged quite successfully by the use of conventional apparatus, securing at the same time lower operating costs and an improved final product, since the omission of the heating or re-running step results in preventing loss of its viscous fractions through cracking.

It will be understood that it is within the range of the present invention to vary somewhat the proportions of the several ingredients used in forming the mixture prior to centrifuging without departing from the spirit or fundamental underlying principle of the invention.

We claim:

1. In the treatment of slop wax distillate to remove undesirable compounds therefrom, the step which consists in adding to such a distillate a small percentage of a synthetic oil formed as a residual product of the polymerization of cracked unsaturated hydrocarbon oil with the use of a metallic halide, whereby to permit of the separation of heavy undesirable compounds from the distillate by a separation treatment based upon differences in specific gravity without heating the latter.

2. A method for treating slop wax distillate which consists in producing a chilled mixture containing 27% of slop wax distillate, 2.6% petrolatum, 0.4% of a residual polymerized unsaturated hydrocarbon oil and 70% naphtha, and without any material heating of said mixture, subjecting the same to separation treatment based upon diiferences in specific gravity to separate from the distillate undesirable heavy wax-like compounds.

3. In a centrifuging dewaxing process, the treatment of slop wax distillate to remove undesirable compounds therefrom, the step which consists in adding to such a distillate a small percentage of a synthetic oil formed as a residual product of the polymerization of cracked unsaturated hydrocarbon oil with the use of a metallic halide, whereby to permit of the separation of heavy undesirable compounds from the distillate without heating the latter.

4. A method for treating slop wax distillate which consists in producing a mixture containing 27% of slop wax distillate, 2.6% petrolatum, 0.4% of a residual polymerized unsaturated hydrocarbon oil and 70% naphtha, and without any material heating of said mixture, subjecting the same to chilling and centrifugal treatment to separate from the distillate undesirable heavy wax-like compounds.

5; In a dewaxing process, the treatment of wax bearing hydrocarbon oil fractions to remove undesirable compounds therefrom, the step which consists in adding to such fraction a small percentage of synthetic oil formed as a residual product of the polymerization of cracked unsaturated hydrocarbon oil with the use of a metallic halide, whereby to permit of the separation of heavy undesirable compounds from the fraction by a separation based upon differences in specific gravity without heating the latter.

RUDOLPH C. OSTERSTROM. CARY R. WAGNER. 

